Sound-conduit



E. H. HAND.

SOUND CONDUIT.

APPLICATION FILED NOV. 5, 1919.

1,346,649, Patented July 13, 1920.

INVENTOR.

j A TT;)RNE Y. I

, UNITED TA S PATENT OFFICE.

ERLE n. HAND, or BA TIMO E, MARYLAND.

' somvn-ooivnufr To all whom it may concern:

Be it known that I, ERLE I-I. HAND, a citi- Zenof the United States, residing at Baltimore city, State of Maryland, have invented certain new and useful Improvements in Sound-Conduits, of which the following is a specification. I p

This invention relates to talking machine tone arms, and its object isto provide a tone arm with a means for so modifying the sounds issuing from the machine, that they are clear, mellow and penetrating.

The object stated is attained by means of a novel combination and arrangement of parts to be hereinafter described and claimed, and in orderthat the same may be better understood, reference is had to the accompanying drawing forming a part of this specification.

In the drawing V Figure 1 is a central longitudinal section of the device, and Fig. 2 is a cross-section on the line 2-2 of Fig.1. 7

Referring specifically to the drawing, 5 denotes a fragment of the tone arm of a talking machine, the same leading to and opening into the throat of the usual horn or sound amplifier, which latter has not been shown, as it forms no part of the present invention. A fragment of the sound-convey ing tube leading from the sound box is shown at G. The sound box has also not been shown as it forms no part of the present invention. Ordinarily, the tube 6 is directly connected to the tone arm 5, but in the present instance there isinterposed between said parts a tone modifier which will now be described.

A tubular conduit has at one end 7 a threaded or other suitable connection with the tube 6, and at the other end 8 with the tone arm 5.- Intermediate its ends, the conduit is enlarged laterally to form an expansion chamber 9 which opens into the interior of the conduit. In order that the chamber may be cut otfmore or less, or entirely from the interior of the conduit, there is mounted in the end 8 a sleeve 10. This sleeve is slidable in the conduit end 8 so tinuation of the end 7 of the conduit and connects the latter directly with the end 8,

both ends of the sleeve being open.

It will be noted in Fig. 1 that the conduit Specification of Letters Patent. Patented July 13 1920 Application filed November 5, 1919.

Serial No. 335,836.

end 7 is slightly flared toward the chamber 9, and the internal diameter of the end 8 is slightly greater than that of the end 7 to accommodate the sleeve 10. It will also be noted that the sleeve 10 is tapered in thicknessin the direction of the part 5, so that when it is advanced to close the chamber 9, its interior will be flushwith the interior of the ends 7 and 8 of the conduit.

For effecting the adjustment of the sleeve 10, a finger button 11 is attached thereto, the shank of the latter extending through a slot 12 in the part 8.

In front of the entrance end of the sleeve 10, or that end which is nearest to the part 7, hangs a gate 13 in the form of a flat circular plate or disk having a radially extending stem 14: by which it is loosely suspended from or pivotally connected to lugs 15 on the inside of the chamber 9. The endof the sleeve 10;is behind the stem 14L, and hence when'the sleeve is advanced as hereinbefore described, to close the chamber 9, said end of the sleeve engages the stem and swings the gate upwardly into the chamber, clear of the sleeve, and when the sleeve is pulled back to open the chamber, the gate drops back to its position in front of the sleeve end. It will be noted that the diameter of the gate 13 is less than the internal diameter of the sleeve 10, and hence when the gate is down, as shown in the drawing, it does not completely close the sleeve but leaves a sufficient space free and unobstructed for the passage of-the sound waves into the sleeve.

lVhen the parts are in the position shown 1 in Fig. 1, some of the sound waves passing through the part 7 toward the chamber 9, eX-

tonal qualities of the instrument as may be desired, andit can also be set to com letely close the chamber as shown dotted in *ig. .1, whereupon the passage of the sound waves is in a straight line and without deflection laterally.

The preferred embodiment of the invention has been shown, but it will be understood that various changes and modifications may be made without a departure from the spirit and scope of the invention as claimed hereinafter.

I claim:

1. A sound conduit having a section provided intermediate its ends with a lateral expansion chamber in communication with the interior thereof, a sleeve slidably mounted in one end of the section, and adjustable to extend across the chamber for shutting off the same from the interior of the section, and a gate opposite that end of the sleeve into which the sound waves pass from the expansion chamber, said gate being dimensioned to partly close said end of the sleeve.

2. A talking machine tone arm having a section provided intermediate its ends with a lateral expansion chamber in communication with the interior thereof, a sleeve slidably mounted in one end of the section, and adjustable to extend across the chamber for shutting off the same from the interior of the section, and a gate partly closing that end of the sleeve into which the sound waves pass from the expansion chamber, said gate being pivoted to the wall of the expansion chamber and engageable by the sleeve to swing into said chamber when the sleeve is advanced to close the latter.

In testimony whereof I affix my signature in the presence of two witnesses.

ERLE H. HAND. Vitnesses E. lVaLroN BnEwiNsroN, HOWARD D. i.\DAMS. 

